https://vital.seals.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://vital.seals.ac.za/vital/access/manager/Repository/vital:5665 Wed 21 Jul 2021 13:46:25 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5710 0.05 in all cases) although seasonal trends were marked, with highest values consistently recorded during the warmer summer months. Investigations into the community structure showed that the ichthyofaunal community within salt marsh was composed almost exclusively of juveniles of estuarine dependant (category II) species, mainly juvenile Mugilidae (<20mm SL) that comprised up to 83% of all fish sampled. Hierarchical cluster analysis and multidimensional scaling did not identify any distinct spatial patterns in the ichthyofaunal community within the salt marsh. The absence of any spatial patterns in the community structure could be related to the absence of any significant spatial patterns in the physico-chemical (temperature, salinity and dissolved oxygen concentrations) and biological (water column and microphytobenthic algal concentrations) variables within the salt marsh (P > 0.05 in all cases). Temporal shifts in the ichthyofaunal community structure within the salt marsh were, however, evident largely reflecting the breeding cycles of individual species within the sub-region. Within the adjacent eelgrass beds, total ichthyofaunal abundances and biomass ranged between 8.4 and 49.4 ind.10m⁻² and between 2.9 and 94.5 g.wwt.10m⁻², respectively. Once again there were no distinct spatial patterns in the abundance and biomass values evident although seasonal patterns were marked. In contrast to the salt marsh, within the in the eelgrass community, there were a large number of adult individuals recorded. Again category II species, the estuarine dependent species, were numerically and gravimetrically dominant. The dominance of category II species reflects the marine dominance of Kariega Estuary. The remaining estuarine utilisation categories did not contribute significantly to abundance or standing stock totals. Hierarchical cluster analysis showed that the salt marsh and eelgrass beds represented two distinct habitats within the Kariega Estuary. Within the salt marsh, the family Mugilidae were numerically dominant contributing 83% of the total catch. Within the eelgrass beds, the sparid, Rhabdosargus holubi and representatives of the family Gobidae contributed 36.3% and 33.9% respectively to the total catch. Estuaries with a wide range of microhabitats have been demonstrated to support a more diverse ichthyofaunal community. Shallow water habitats in general are important areas for juvenile fish within estuaries. Taylor’s salt marsh provides an alternative shallow water habitat, occupied by a distinct ichthyofaunal community composition, with increased food availability and decreased predation pressure, for a wide range of fish species.]]> Wed 12 May 2021 20:18:30 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4966 Wed 12 May 2021 18:26:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:694 Wed 10 Aug 2022 06:00:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4023 Thu 13 May 2021 08:13:31 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5286 Thu 13 May 2021 08:12:56 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:14959 Thu 13 May 2021 04:53:00 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5292 Thu 13 May 2021 04:43:08 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:4710 Thu 13 May 2021 04:02:14 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:5244 7,0), or on nitrate or calcium levels, and did not conclusively increase the redox potential of the water. Residual ozone concentrations up to 0,04 mg/l in a sixhour treatment had no harmful effects on rainbow trout, and there were no signs of gas-bubble disease arising from supersaturation of the water with oxygen. Activated carbon filters were effective at removing residual ozone from the water after treatment. Treatment of the water with oxygen alone had no effect on nitrite concentrations.]]> Thu 13 May 2021 00:46:52 SAST ]]>